The present invention is directed to apparatuses for tilting light assemblies, and more particularly, to apparatuses for tilting light assemblies mounted to extendable towers on lighting systems.
Mobile lighting systems are used extensively to provide necessary light for outdoor and other work sites lacking adequate ambient lighting. Conventional mobile lighting systems often comprise an extendable light tower and an electrical power generator mounted to a trailer. The extendable light tower can be raised to provide the desired illumination once the trailer has been properly situated at a work site. Typically, the extendable light tower will be rotatably mounted to the trailer so that the lights can be aimed in different directions by rotating the tower relative to the trailer. This rotation can provide a means for changing the horizontal direction of the lights. To provide proper illumination at a work site, however, it is often also necessary to change the vertical direction of the lights by adjusting the tilt angle of the lights relative to the extendable light tower.
Adjusting the tilt angle of the lights relative to the extendable light tower using conventional systems often requires lowering the tower back down toward the ground so that the light assembly can be adjusted by hand. The extendable light tower must then be raised back up again to check the tilt angle. Frequently, this process is repeated several times before the desired tilt angle is achieved.
Various devices for tilting the lights on mobile lighting systems have been produced and they fit into two basic categories. The first category of tilting device utilizes powered servos or motors that are remotely controlled on the ground. These systems can be expensive and unreliable, and as such they do not fit well into an overall mobile lighting system scheme of being simple and inexpensive.
The second category of tilting device utilizes a system of cables and mechanical controls running from the lights to the ground. These mechanical controls are manually operated on the ground to tilt the lights on the extended tower. The complexity of this type of tilting device is difficult to incorporate into the telescoping light towers so often used with mobile lighting systems today. As a result, no commercially viable form of this tilting device is currently known. Based on the foregoing, a mobile lighting system having an inexpensive light tilting apparatus reliably incorporated with an extendable light tower would be desirable.
A light tilting apparatus that can be incorporated with an extendable tower is provided. In one embodiment, a mobile lighting system includes a tiltable light assembly mounted to an extendable tower. The tiltable light assembly includes one or more lights and the light tilting apparatus of the present invention. In one aspect of this embodiment, the light tilting apparatus includes a tilting member pivotally mounted to the extendable tower so that pivoting motion of the tilting member results in tilting of the lights relative to the extendable tower. A linkage positioned substantially parallel to, and offset from, the extendable tower is operably connected to the tilting member at one end and has a catch on a distal end away from the tilting member. A linkage regulator attached to the extendable tower has a guide portion for the linkage to pass through as the extendable tower is extended and retracted. The linkage regulator is configured to engage the catch on the linkage when the extendable tower reaches a preselected extension preventing further motion of the linkage in the direction of tower extension.
As long as the linkage is free to pass upward through the linkage regulator, springs keep the tilting member angled at a maximum upward angle and in contact with a limit restrictor. When the linkage regulator engages the catch on the linkage, the halted linkage causes the tilting member to begin rotating downward, resulting in a tilting of the lights downward. Continued extension of the extendable tower results in more downward tilting of the lights, ultimately coming to rest at a maximum downward tilt angle when the extendable tower is fully extended. Retraction of the extendable tower from this fully extended position will accordingly allow the lights to tilt upward. To tilt the lights to a desired angle, the extendable tower is extended until the catch on the linkage just engages the linkage regulator. By controlling further extension of the extendable tower after engagement, any tilt angle of the lights between the maximum upward tilt angle and the maximum downward tilt angle can be achieved.